Safety device for electric vehicles



A rii s, 1924. 1,489,855

F. STEINER-FREY SAFETY DEVICE FOR ELECTRiC VEHICLES Filed March 27, 1923 Patented Apr. 8, 1924.,

FRITZ STEINER-IEREY. O F BER-NE; SWITZERLAND. ASSIGNOR T0 SOCIETE ANONYME DES ATELIER-S DE SEGI-IERON, OF GENEVA, SWITZERLAND, A CORPORATION OF SWITZERLAND.

SAFETY DEVICE FOR ELECTRIC VEHICLES.

Application filed March 27, 1923. Serial No. 628,007.

To all to 700m it may concern:

Be it known that I, FRITZ STEINER-FREY, a citizen of Switzerland, residing at Borne, Canton of Berne, in'the Confederation of Switzerland, have invented certain new and useful Improvements in Safety Devices for Electric Vehicles, of which the following is a specification.

In the case of electric traction service by a single man per locomotive it is'advisable to arrange the controlling devices in such a manner, that if the operator takes his hands off the controller handle while the vehicle is in motion the supply of current to the driving motors is automatically switched off and the emergency brake applied.

Such devices have heretofore been customary on underground and suburban railways and are commonly termed dead mans handle feature of the controller. The traction service on these railways is generally very uniform and the roads show no Very heavy down-grades.

The device usually consists of contacting members which are under the control of the drivers controller handle, the contacts beingseparated as long as the drivers hand is firmly gripping the handle, whilst the contact is established if the driver releases his hold on the handle, for instance if he meets a sudden accident, say an epileptic fit, or if for some other reason he interrupts or neglects his duty. It is generally possible to suspend the operation of the safety device by turniug the handle onto the zeroposition or by bringing the reverser switch into a zero-position. In this case the emergency brake remains inoperative in the hith erto known safety devices.

The present invention aims at enabling the use of the so-called dead-mans handle also for locomotives and motor cars of interurban railways. In order to measure up to the necessary requirements the device must fill the two following conditions which usually may be altogether neglected in the case of underground and suburban railway. service:

First of all the driver must be able to release his controller handle without interrupting the current feeding the motors and without operating the emergency brakes. This condition is of importance for the switching service of the locomotives in the yards where the driver is compelled to carefully watch the signals and signs of the switching crew for which purposehe must lean out of the window of the cab.- Since the switching service is always performed at low speeds, the condition to be filled is such that means must be provided for causing the safety device to become inoperative at speeds which are lower than a given predetermined slow speed limit within which practically no danger is incurred.

A second important condition is this that if the speed of the locomotive or motor car exceeds the said predetermined no-danger limit the controller handle may be moved into the Zero-position on down-grades in order to disconnect the motors from the feeding current without that portion of the safety device which provides for the throwing on of the emergency brakes becoming inoperative.

The safety device according to'this invention fulfills these conditions in a simple manner. The particular feature of the device which in a known manner provides for the cutting out of the motors when connected to the feeders and for making the emergency brakes operative whenever the driver releases his controller handle. consists in a member which is controlled by the speed of the locomotive or motor car and makes the safety device inoperative as long as its speed does not exceed the said predetermined no danger limit.

On the other hand the operation of the safety device being independent of the position of the controller handle the latter may be brought into the'zermposition, or the motors may otherwise be disconnected from the feeding line, or the reverser may be brought in a zero-position, whilst the release of the handle by the driver or say the interruption of his duties which includes the keeping open a contacting device connected with said handle, will, provided the speed at the time exceeds the predetermined no-danger limit at once make the emergency brake operative.

The drawing represents by way of example diagrammatically one working form of the invention.

1 is the controller, 2 the controller handle of a vehicle (not illustrated). The controller handle 2 is furnished with a contacting device like those customary in the so-called dead mans handle, and consisting for eX- ample of a pin with knob 3, a spring t and the contacts 5 and 6.

A speed governor driven from an axle oil? the vehicle causes the separation of the contacts 9-10 if the speed of the vehicle is within the predetermined no-danger limit say 10 km. /hr. whilst they are .connected by said speed governor when the locomotive speed exceeds said limit. One of the contact pieces 9 is connected by the conductor 7 to the contacting device of the controller handle whilst the other contact piece 9 is connected over the conductor 11 to the electrically operated brake valve 131 l. If the conductor 11 is carrying current the air will be discharged from or flow into the main brake pipe 15 if in the particular case the brake be an air pressure or a vacuumbrake. v

The conductor 11 is connectedby means of conductor 12 for instance to operating members of the locomotive main switch, so that the latter causes the motors to be out of? whenever the conductor 12, owing to the release of the dead mans handle by the driver receives controlling current.

It on a down-grade travel the motors are disconnected from the feeding line, the driver nevertheless is compelled, whenever the speed is beyond the predetermined nodanger limit, to continuously keep his hand on the controller handle, as he has no other means at all to prevent the safety device from throwing the emergency brakes on.'

The working manner of the describedl working device is as follows:

hen running at normal speed the driver causes the contacts 5-6 to be separated by firmly gripping the knob 3. The contacts 9-10 are connected it the peed exceeds the non-danger limit of for instance 10 km. per hour. It the driver for some reason or other becomes incapacitated or if he re leases his grip on the dead-mans handle, the contacts 5 and 6 will become connected. In this case the conductor 7, the contact members 9-10, the conductor 11, the electric relay 13 of the valve brake, and the conductor 12 leading to the operating member of the main switch will be fed with controlling current derived for instance from a battery and thereby the motors will become disconnected from the feeding line and the emergency brake will be made operative.

During switching service, that is to say at small speeds for instance not exceeding 10 km. per hour, the driver is free to release his grip of the controller handle without causing either the emergency brake to become operative or the motors to be dis connected. This is due to the fact that the worxing current for operating the brake relay 18 and for the conductor 12 leading to the operating member for disconnecting the motors is now interrupted, the contact 910 being separated owing to the low speed or" the governor 8.

When running down-grade the driver may bring the controller handle 2 into the zero-position, that is to say he may run with disconnected motors without that portion of the safety device which causes the emergency brake to be thrown in, becoming inoperative. Owing to this arrangement the safety device is ever ready to become operative as soon as the speed of the locomotive or vehicle exceeds the predetermined no-danger limit. Therefore the action of the emergency brake is also available on the down-grade travel when the motors have been disconnected.

Any other suitable device depending upon the speed of the vehicle and which causes the separation of the contacts 91() as long as the predetermined no-danger limit is not attained, may be substituted for the speed governor as hereinbetore described.

I claim as my invention- 1. A safety device for electric vehicles specially for one man service, comprising mem bers for disconnecting the driving motors from. the feeding line and for operating the emergency brake whenever the driver fails to give personal attention to said means, and means controlled by the speed of the vehicle and adapted to render the safety device inoperative as long as the vehicle speed remains below a predetermined limit.

2. A safety device as in claim 1, the motors becoming disconnected from the feeding line and the emergency brakes being thrown on when the safety device hecomes operative.

8. A safety device as in claim 1, the emergency brakes being thrown on when the safety device becomes operative with the vehicle running with the motors disconneoted from the main line.

4. A safety device as in claim 1. comprising in combination electric conductors adapted to be disconnected by the drivers hand gripping the controller handle, an element con trolled by the speed of vehicle and adapted in a circuit which is independent from the to interrupt a circuit in said electric conmotor circuit. 10 ductors whenever the speed does not exceed In testimony whereof I have atfixed my a predetermined no-danger limit, an air signature in presence of two witnesses.

5 brake valve adapted to be operated by elec- FRITZ STEINER-FREY.

tric current, a main switch for disconnect- Witnesses: ing the motors from the feeding line, and a KARL WERZ,

member adapted to operate the main switch ADOLF AMMANN. 

